Field of the Invention and Description of the Related Art
The present invention relates to an endoscope image processing system that even when an endoscope image area and a character image area to be displayed on a monitor using video signals are changed, image processing can be performed in such a manner as adapted for each area.
Recently, there have been widely employed endoscopes (referred to also as scopes or fiber scopes) which enable an operator to observe body organs or the like by inserting an elongate insert section into the body cavity, and also to perform various medical treatments by using appliances inserted through an appliance channel at need.
Various types of electronic scopes having image sensing means, which comprises a solid state image sensor such as a charge coupled device (abbreviated as CCD) and are built therein, are also used. These electronic scopes have such advantages as a higher degree of resolution than fiber scopes, easy recording and reproduction of images, as well as easy image processing including enlargement of images and comparison of two image screens, for example. In view of the above, there is further employed an apparatus of the type that a TV camera is mounted at an eyepiece of a fiber scope to realize nearly comparable functions to those of an electronic scope (the apparatus being referred to as TV camera integrated scopes).
An endoscope image outputted for visual display from image sensing means of an electronics type scope given by the above electronic scope or TV camera integrated scope is converted into a video signal added with character information such as letters (or a character image) for indicating information needed to identify the endoscope image, the video signal being recorded in a large capacity recording device such as a hard disk unit or magneto-optical disk unit.
Because the number of pixels used in the image sensing means of the electronics type scope is less than resolution with which a monitor can display and the display screen of a monitor is horizontally long in general cases, an area where no endoscope image is displayed occurs at the end of the image screen in the horizontal direction. Usually, a video signal containing an endoscope image and character information added thereto is created so as to display letter information in such an area where no endoscope image is displayed.
A method of recording the video signal containing an endoscope image and character information added thereto is mainly divided into analog type and digital type. The digital type method is superior to the analog type method in a point of maintaining image quality. When recording data by the digital type method, however, since an extremely large amount of data must be handled, it is usual to carry out processing called coding compression, followed by storing the reduced amount of data in a recording device.
In an attempt to perform the coding compression, there occurs a considerable difference in the time required for calculations and the data amount after calculations between the case of compressing one pixel as a multi-value image like a color image represented by 24 bits, for example, and the case of compressing one pixel as a two-value image like a monochromatic image (or character information) represented by 1 bit. When using the digital type method to record image information for a screen in which a colored endoscope image is present only in a particular area and monochromatic letters are displayed in the remaining area, like a monitor screen of an endoscope device, it is therefore effective to divide the entire screen area into twos and process data in different manners of compression corresponding to the respective areas.
One easily conceivable method for division into two areas is practiced by specifying the construction of an input screen in advance at the side of an image processing unit and dividing the screen into a multi-value (three or more-value) image area and a two-value image area in accordance with the specifications. Another conceivable method is effected by an operator who designates a way of division into two areas through area designating means, as disclosed in Japanese Patent Laid-Open No. 2-112378.
With the former method of specifying the construction of an input screen, however, some of endoscope devices display a color image in a larger area than others. This implies that when the image processing unit sets the boundary between a color area and a monochromatic area, the boundary must be set in match with the maximum area for a color image available among a variety of endoscope devices.
Accordingly, the former method suffers from a disadvantage of requiring longer time for compression calculations and data transfer than necessary and increasing an amount of data in the case where such images of endoscope deices as having a small color image area, i.e., a small endoscope area, in the screen.
On the other hand, the latter method of dividing the screen into two areas by the area designating means has a problem of enlarging a burden imposed on the operator because a mouse, tablet or the like is required as the area designating means and the operator has to carefully input each image area.